Let’s get one thing straight: The Home Theater Glossary is not a brand-new app. That said, knowing what you’re talking about never gets old, right?

From frequency response to contrast ratio, this extremely helpful app provides an easy reference point. The app itself allows you to search for terms or browse alphabetically. Developer Deep Powder Software says that they also welcome feedback — directly through the app. That means if you see something missing or incorrect, you can contact them to make it right.

This app used to be available for all platforms. However, it seems to have disappeared from iTunes. At last peek, Android users could still snap this one up for $2.90.